Question: $ { {5} \times \left[\begin{array}{rrr}{1} & {2} & {4} \\ {3} & {4} & {4}\end{array}\right] = {?} } $
Solution: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rrr}{5}\times{1} & {5}\times{2} & {5}\times{4} \\ {5}\times{3} & {5}\times{4} & {5}\times{4}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{5} & {10} & {20} \\ {15} & {20} & {20}\end{array}\right]}$